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Old 02-16-18, 02:16 AM   #1935
AC_Hacker
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Quote:
Originally Posted by Roostre View Post
It took me a long time, but it's done. Whew.

What a great thread and resource for the DIY experimenters out there.

I found that the "Closed-Loop/Ground-Source Heat Pump Systems - Installation Guide" can be found for a bit less and ordered a copy. It is from 1988 so I hope it's not too outdated.

The section on Heating and Cooling Degree Days led me to develop this chart based on a local weather station:
Attachment 8156

My heating bill from January of 2017 shows it to be an exceptionally cold month. By back calculating the Therms it looks like the house required about 25,000 BTU/hr to maintain.

The loop is going to be the most challenging aspect I can foresee; after researching local laws it turns out that you cannot drill deeper than 30 feet without a permit from the state AND you must be a certified driller.

For a horizontal loop install we do have a decent sized backyard at about 100 feet deep and 110 feet wide. The "installation Manual" should be of great help here.

I plan to make a fusion tool fashioned after your design and spend a good deal of time practicing until my joints are 100% solid.

Thanks again for this manifesto. It excites me that such leverage exists to be harnessed by all with a little education and effort.
Glad you want to get your project going. before you begin your loop, you should try to find out everything you can about soil conditions. Ask local well drillers and ask local GSHP installers. It really helps to know what's down there before you begin.

My lot size is very small, so I could only drill down. Sounds like you have more property and trenches would be easier to do. After I did mine I happened to look at the cost to rent equipment for digging serious trenches, and it was not so bad.

Also consider what the frost line is in your area, very important.

Vlad built an amazing drilling machine that totally kicked ***. If you think you might want to do this, I can give you some general information. Vlad is a very unusual guy with lots of skills. He drilled 50 foot holes I believe.

Renting a back hoe is way easier.

Regarding my pipe fusing tool, it worked very well. I used it to weld 'butt joints', where two molten pipe faces are welded directly together. A little practice and experimentation is called for. I would caution you that in my method, I made all of my 'U-Turns" at the bottom of the hole with three butt welds each. I had sixteen holes, plus a few extra welds. All together that was a lot of welds. Each weld had a bit of 'roll' inside the pipe, which causes some amount of friction. If you over-heat the pipe face, and use lots of pressure holding the two pipe faces together, the roll will be bigger (more friction). However if you practice and get just the right amount of heat & pressure you can make a good weld with very little roll. I did some testing and calculating on my loop, and the large number of butt welds cost me some friction loss.

If you go for trenches, you will not encounter very many welds, so a smaller number of butt welds won't make much difference in friction.

There is also another system called "Socket Welding". If you check it out, it leaves no rolled HDPE inside the pipe.

Vlad bought a socket welder from ebay, and it worked for him. I borrowed it and discovered that the Heating Sockets, which are coated with Teflon, would fit and function perfectly on my little home made paddle. The cost of a pair of those sockets was not too much. Might want to look into that. Maybe rent one local. I did check out rental, and was offended by the price, so I built my paddle-welder instead. I found out about socket welding after the fact. The butt welds are very strong, the equipment is cheaper. Your choice.

If you can tell me your Zip Code and the beginning and end of your worst heating month, and the therms used in that billing period, I will double check your numbers... couldn't hurt.

By the way, Ecorenovator "randen" dug trenches for his very successful system. He is probably watching this thread, but if he doesn't weigh in, please contact him, he has much GSHP lore to share. He built two heat pumps, one was fairly easy, it was 2.5 Tons, the other was three-phase and 3-Tons. He had problems on the second one, in part because a pre-used compressor failed.

Good luck on your project, you will have much support here.

Photographs of your undertaking always helps.

Best,

-AC_Hacker
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